The caseinolytic protease from E. coli is comprised of two subunits: the protease, ClpP, and the ATPase, ClpA. Fully active CIpP has been over-expressed in E. coli and purified to homogeneity. Mass measurements from the STEM indicate that it is a tetradecamer. In stain, it appears as two stacked seven-member rings. Small angle X-ray and neutron scattering curves were determined for CIpP in solution. A model was derived from these data of a cylinder with an axial pore. The size of the pore is similar to that found in chaperone proteins. CIpP has been crystallized and the above data has been used to help in solving the x-ray structure. ClpA has been examined in the STEM. Preliminary samples were not very good but fi~rther attempts with better purified samples are underway. The ClpA component may be hexameric. The final goal is to look at the interaction of ClpP and ClpA.